Fixed the state of the “Mark All” checkbox

Author: dtdesign

ts/WoltLabSuite/Core/Component/GridView/Selection.ts

@@ -54,7 +54,16 @@ export class Selection {
     if (forceValue === undefined) {
       if (this.#markAll !== null) {
         const markedCheckboxes = checkboxes.filter((checkbox) => checkbox.checked).length;
-        this.#markAll.indeterminate = markedCheckboxes > 0 && markedCheckboxes !== checkboxes.length;
+        if (markedCheckboxes === 0) {
+          this.#markAll.checked = false;
+          this.#markAll.indeterminate = false;
+        } else if (markedCheckboxes === checkboxes.length) {
+          this.#markAll.checked = true;
+          this.#markAll.indeterminate = false;
+        } else {
+          this.#markAll.checked = false;
+          this.#markAll.indeterminate = markedCheckboxes > 0 && markedCheckboxes !== checkboxes.length;
+        }
       }
     } else {
       for (const checkbox of checkboxes) {